Identification And Expression Analysis Of OVATE Transcription Factor Family And The Genes Cloning Of VvOFP8 And VvOFP17 In Grape

OVATE family protein(OFP)is a class of transcriptional repressor which regulate plant growth and development.OFP has been studied in Arabidopsis,tomato and rice.And some OFPs control fruit shape of Arabidopsis and tomato.Fruit shape is an important appearance quality of grape,so it is important to study the molecular mechanism of fruit shape.In this study,grape OVATE transcription factor family was comprehensive identified and biological information was analyzed.Then,to explore the expression patterns of the family members,quantitative real-time PCR(qPCR)was used.In the last chapter,VvOFP8 and VvOFP17 were cloned from the Houman grape variety.Biological information analysis and expression characteristics of the two genes indicated that they maybe regulate grape fruit shape.The main results were as follows:1.Seventeen putative VvOFPs were identified in the grape genome and unevenly distributed on the eleven chromosomes.No intron was found in the gene structures of VvOFPs.The VvOFPs encoded hydrophilic proteins,containing 115-444 amino acids,and their isoelectric point ranged from 4.55 to 9.69.In addition,all the VvOFPs contained the entire OVATE domain and were predicted to be located in the nucleus,All but VvOFP9 contained some Nuclear Export Signal(NES)conserved residues ranged from one to eleven,while most VvOFPs contained one or two conserved residues.Phylogenetic analysis suggested that OFPs from grape and Arabidopsis could be divided into 6 groups(Ⅰ-Ⅵ).Group Ⅱ,Ⅲ and Ⅴ contained only two members,whilst members of group Ⅰ,Ⅳand Ⅵ were clustered in the species-specific pattern.VvOFPs and AtOFPs contained 10 uncharacterized motifs.Motif 1 and 2 were located in the OVATE domain region.Besides,group-specific motifs were also found outside the OVATE domain.2.The results identified VvOFPs with different tissue-specific expression patterns.Most VvOFPs were more highly expressed in roots,stems and flowers,while a little gene was detected with low level in leaves and fruits;VvOFPs expressed differently in fruits at different developmental stage.Expressions in flowers a week before or at anthesis were at a high level,while lower in fruits four weeks after anthesis.Two pairs of paralogues(VvOFP1 and VvOFP17,VvOFP9 and VvOFP15)exhibited the same expression patterns,while the other four pairs of paralogues(VvOFP6 and VvOFPIO,VvOFP3 and VvOFP7,VvOFP2 and VvOFP11,VvOFP4 and VvOFP8)exhibited diverged expression patterns.Some VvOFPs exhibited the similar expression patterns such as VvOFP6 and VvOFP7 which were expressed at the highest level in flowers one week before anthesis,and they may have the overlapping function.3.The VvOFP8 contained a 1191-bp ORF and encoded a 396 amino-acid polypeptide.The VvOFP17 contained a 1209-bp ORF and encoded a 402 amino-acid polypeptide.Compared with the NCBI login sequences,mutations occurred in both sequences.OVATE domain was conserved in both sequences.Secondary structure contained many random coils.VvOFP8 was localized in the cytoplasm and was predicted to probably contain a coiled coil structure in the OVATE domain region.VvOFP17 protein was localized in the endoplasmic reticulum and nucleus containing two NLSs,and one transmembrane region in the N-terminal.The evolutionary of OVATE proteins between the two proteins and other plants was consistent with the evolution of species.Functional prediction showed that VvOFP8 and VvOFP17 played roles in transcription regulation in the courses of central metabolism and cell membrane respectively.Expression analysis results showed that the expression of VvOFP8 in two species at anthesis was the highest,and expression level of round fruit cultivar was higher than the elongated fruit.The expression peak of VvOFP17 in round fruit cultivar was in two weeks after anthesis,and for the elongated fruit cultivar,the expression was the highest at anthesis.Therefore,it was inferred that different expression patterns of VvOFP8 and VvOFPl 7 may affect the grape fruit shape.